Question

Which function has a vertex on the y-axis?

O f(x) = (x - 2)^2
O f(x) = x(x + 2)
O f(X) = (x-2) (x+2)
O f(X) = (x + 1) (x - 2)

Answer 1

(x-2)(x+2)

Explanation:

• first: the function that represent on graph as a curve with vertex it must be a quadratic function of second degree, so we have here 3 equation of second degree which are after simplifying will be :

`x^(2) - 4x+4`

`x^(2) - 4`

`x^(2) -x -2`

• Second if the vertex of curve is on Y axis therefor X must equal 0

• to find the vertex of curve we use this rule x -coordinate =-b/2a
• in this equation
  `x^(2) -4` -0/1 =0 so here x coordinate =0 so its vertex is on y axis